HOUSTON -- NASA astronaut and U.S. Navy Capt. Mark Kelly has announced his plans to retire from the agency on Oct. 1. He is a veteran of four space shuttle missions.

"We salute Commander Mark Kelly and his contributions to NASA as an extremely accomplished member of the astronaut corps and the final commander of the space shuttle Endeavour," said NASA Administrator Charles Bolden. "We deeply respect his achievements and his decision to focus on his family. We continue to send out our thoughts and prayers to Mark and his wife, Rep. Gabrielle Giffords, as she makes a remarkable recovery. We know that Mark will continue to do great things for his country no matter what he chooses to do next. He has helped us build a space program poised to take advantage of the many opportunities in our bright future."